Fuse plug or the like



Jan. 31, 1933. E. J. BURNS FUSE PLUG OR THE LIKE Original Filed Jan. 25, 1929 gw'ntoz [DH 4RD J. EUR/V5 Patented Jan. 31, 1933 UNITED STATES PATENT OFFICE EDWARD J. BURNS, OF. FALL RIVER, MASSACHUSETTS, ASSIGNOR TO SEARS 1B. CONDIT, OF BOSTON, MASSACHUSETTS FUSE PLUG OR THE LIKE Application filed January 25, 1929, Serial No. 335,046. Renewed January 23, 1981.

My invention relates to a fuse plug for electric circuits which prevents over fusing of the circuit by inserting a coin or tin foil into a cut-out or by the use of a fuse of larger 5 amperage than is proper for the circuit.

' Very often when a fuse blows and another one is not easily obtainable, a make shift connection, such as tin foil or a coin, is inserted into the socket to close the circuit. Such an expedient, although serviceable for the time being, really defeats the purpose of the fuse plug where the circuit closer is of higher fusibility than the wire in the system since the wire will melt. The melting of a wire in the circuit, such as one passing in close contact to wood, would give rise to fire.

The fuse plugs now found on the market are made in several sizes, that is to say that the fusible element is varied to fuse at-diferent amperages. The conventional fuses are about five in number and range from thirty to ten amperes. It will be seen that in the event a ten ampere fuse should be blown and a twenty-five ampere substituted therefor, that the circuit would lose. its safety factor inasmuch as the substituted fuse would have a fusibility above the danger point. By the use of my proposed fuse plug, where the same is madeup in forms peculiar to each amperage, it will be impossible to interchange a fuse plug of higher amperage for one of lower amperage and conversely. As w1ll be appreciated, by making the portion of the fuse plug which remains permanently within the socket of different tapers and the recesses of fuse carrying elements of different tapers, each taper corresponding to a certain amperage, that it will be hardly possible to substitute a fuse carrying element of one amperage for that of another.

It is an object of my invention to provide a fuse plug which is simple in structure and reliable in operation.

Another object of my invention is to provide a fuse plu which is fool proof and precludes the possi ility of forming a makeshift connection in the socket after the fuse has blown or the use of a fuse of larger amperage.

Still another object of my invention is to provide a two part fuse plug wherein one of wholly of porcelain and having the ferrule the complementary parts remain permanently attached within the plug socket, the other or removable part containing the fuse element; the component parts being made in varying amperage sizes, each having a different taper 5 so that the fuse carrying members cannot be interchanged.

Other objects and advantages of my invention will be apparent from the detail description which follows.

I attain these objects and advantages by means of the device illustrated in the accompanying drawing wherein:

Figure 1 is a front elevational view of the female fuse carrying member.

Figure 2 is a cross sectional view taken through the two members of the fuse and showing the two members just about ready to be joined together.

Figure 3 is a bottom view of the lower or male member.

Figure 4 is a cross sectional view of a modification wherein the lower member remains unchanged, but the upper member is made member attached thereto by means of projec- 'tions.

Figure 5 is a perspective view showing the ferrule member which is secured to the female fuse carrying member for the purpose of closing the circuit through the male member.

Similar numerals refer to similar parts throughout the several views.

Referring to the'drawin g, the fuse plug consists of the complementary members 1 and 2 which are hereinafter referred to as the female fuse carrying member and male member respectively. The male member 2 is adapted to be permanently affixed within a cut-out by means of the clips 3 which prevent its withdrawal. The member 2 may be formed of any insulating material, such as porcelain or hard rubber, and is provided with a disc member comprising a center contact 4 which is attached to a rivet member 5. The member 2 is provided with a tapered portion or boss 6 which is part of said member and is formed at the same time that the member is made. The portion of said tapered portion, adjacent its base, is straight and an annular groove 7 is provided between said base portion and the remainder of the male member 2, the disc member 4 forming the bottom of said annular groove. The upper member 1, known as the female fuse carrying member,'is provided witlra metallic cnpzmember which comprises a center contact 8 which has a configuration substantially the-sameas the tapered portion .6 and .is adapted .to fit thereon, the base or rim '9 of said cup being adapted to fit within the groove"? and to contact the plate 4. Surrounding the :member 1 is the threaded shell 10 which is shown to be a narrow bandto prevent itsahenrg slitted-fand carried underthe rim 9 for the purpose of providing a "makeshift connection. A fuse 1 1 passes fromtheshell .510 to the -top enclosed part "of theantatllic -'cup 8. A window I2 is provided as is conventionally done in fuses. A 11 explosion'chamher "-13 is also provided.

Referring to themo'di'fication, 'the change is made in the female fuse carrying2member "-in that instead of providing the inetallic cup 8, a ferrule member 15 is provided which has projections 16 which are inserted'into openings provided therefor in the porcelain body of the fuse. The fuse carrying member is made to have a tapered recess forthe apurpose described before. 'In all other respects *the modification is substantially the same "as the -=s'tru'cture described in connection with Figure 2. I

'ZUhe manner of use of the above described fuse plug is as follows. The lower or male -member is firs't inserted in place by forcing it into the socket. By means o-f the finsprovided on the e'dge of said member, it is held :in place against removal. The upper "or female member 1, containing the fusible ele- ':men"t, is the:on1y replaceable part of the fuse plug unit and *is screwed in place unti lit hugs the conical portion of the lower member and :contact is made. *In the event that the fusiible element is blown, the entire'aipper part "I is removed and a new one substituted. 282s previously stated, the male and *female memiber's may be fmade up in different sizes with different tapers, each taper being peculiarto the size of the fuse. This may be done by varying the depth of the male member or changing the size of the -annular groove and also ;chan'ging=the'female fu'se earrying memaber a corresponding amount. 'By "reason of tt-he fact that the socket iemploying the pro- "posed ifuse is not suited to receive a fuse of higher vamperage nor is adapted to be "closed by ta :cein aor other imakeshi ft, the Tire hazard from the fusing of electrical wiring from excess current is eliminated.

.Ail l'ithat fhas beensaidabove in the='descripztion of any preferred embodiment is offered by way :of iillustrationiand not limitation. I do not wish to ibe limited to the exact struc- :ture of the preferred embodiment shown :and

dcscribed, or to :any particular imat er-ial *use'd in the construction of parts, or to the design of parts, but desire protection as against any variations in structure which utilize the principle of my invention and fall within the purview of my invention and are within the spirit and claims-: v

The invention having been set forth, what is claimed .as new and useful is.:

1. In cornbinationwith a cut-out, a fuse plug comprising two complementary members,-.one of said members being adapted to be permanently inserted within said cut-out scope of the following and hawingcaiaperediportionthereon of insuher, a male member complementary to said fuse -'carrying member, :said anale member being adaptedfto be permanentlyiinserted said cut-out, said "male member having a tapered portion of insulating anazterial thereon, an annular groove within said maile member adjacent the base :of said itapered portion, a metallic disc in sa id groove adapted to contact the center contact of the icuts'out, ,saidfemale iEu-se c ar-ryin'g member (comprising a body of insulating material having a :re-

are

cessed portion therein corresponding to lthe tapered portion on said male member ascrew shell on the exterior o f said fuse caarrying member, an annular conductor secured "to said body adj acent said recess and protruding below, a fusihle'element passing Efrem said annulanconduc'tor to said-screw shell o fsaid female fuse carrylng member, said annular conductor being adapted to slide into said annular groove when -the fuse carrying unemher is in position to "c'losethe circuit.

'3. In combination with a cutent, a fuse plug comprising two -'comp'lemen'tary members, one of said members being adapted to be permanently inserted within said cat-out and having a tapered portion thereon of insulating material, said member having a circiilar'groove at the base of said "tapered portion, a conductonwi't-hin said groove which is adapted *to make contact with the center contact of the cut out, the other com- "plementary member having a tapered recess therein, a. metallic *cup like member within said recess havin g a ski rt portion adapted to fit within said circular groove and electrically contact the conductor within :said groove,

said second member having a fusible element therein.

4. In combination with a cut-out, a fuse lug comprising a female fuse carrying memr, a male member complementary to said fuse carrying member, said male member being adapted to be permanently inserted within said cut-out, said male member having a tapered portion of insulating material thereon, an annular groove within said male member adjacent the base of said tapered portion, a metallic disc in said groove adapted to contact the center contact of the cut-out, said female fuse carrying member comprising a body of insulating material having a recessed portion therein corresponding to the tapered portion on said male member, a screw shell on the exterior of said fuse carrying member, a metallic cup like member within said recess having a skirt portion protruding below, said skirt portion being adapted to slide into said annular groove when the fuse carrying member is in position to close the circuit.

5. In combination with a cut-out, a fuse plug comprising two complementary insulatlng members, one of said members having a raised portion thereon, the other of said complementary members having a fusible element, a recess corresponding to said raised portion and a screw threaded shell which is connected with said fusible element and screws into said cut-out, a conductor adjacent the base of said raised portion, and conductor means in combination with the recess for contacting said conductor, said fusible element being connected with said conductor means.

6. A cut-out comprising a contact, an insulating member overlying said contact and having a passage leading thereto and a raised portion, and a fuse-carrying member having a recess which receives said raised portion and a contact which projects beyond said member and enters said passage and en ages said aforesaid contact.

A cut-out comprising a contact, an insulating member which extends above said contact and has a passage leading thereto and an insulating raised portion, and an insulating fuse-carrying member having a recess which receives said raised portion and a tubular center contact which projects beyond the end of said member and enters said passage and surrounds said raised portion and engages said contact, a fusible element in said fuse casing member connected with said tubular shell surrounding and carried by said fuse-carrying member and connected with said fusible element.

8. A cut-out comprising a contact, an insulating member which extends above said contact and has a passage leading thereto and a raised portion, and an insulating fusecarrying member having a recess which receives said raised portion and a projecting center contact which enters said passage and a screw-threaded annular shell which surrounds said fuse carrying member, and a fusible element connected between said shell and center contact.

9. A cut-out comprising a contact, an insulating member which overlies and carries said contact and has a passage leading thereto and a raised portion, and a fuse-carryin member having a recess which receives sai raised portion and a contact which projects beyond said member and which enters said passage and engages said first-named contact.

10. A cut-out as defined in claim 9, wherein said passage is annular and the contact of said fuse-carrying member also is annular and encloses both said recess and said raised portion, and a screw-threaded shell surrounding and carried by said fuse-carrying member and constituting a terminal thereof.

11. A fuse plug comprising a fuse-carrying member and a separate insulating member, said insulating member having an annular passage leading from its top face and a center contact at the bottom of said passage having a part that is exposed at the bottom of said insulating member, said fusecarrying member having an annular center contact that projects beyond its end and enters said passage of said insulating member and engages said center contact thereof.

12. A fuse plug as defined in claim 11 wherein said passage is annular and said insulating member has a raised portion located within the area of said passage, said fusecarrying member having a recess which receives said raised portion, and said center contact of said fuse-carrying member being annular and enclosing both said recess and said raised portion, and a screw threaded shell surrounding and carried by said fusecarrying member and constituting a terminal thereof.

13. A fuse plug as defined in claim 11 wherein an insulating boss is seated upon the center contact of said insulating member in said passage and upstands thereabove, and said fuse-carrying member has a recess which receives said boss, said center contact of said fuse-carrying member being annular and enclosing said boss and recess.

14. A cut-out comprising a contact, an insulating member overlying said contact and having an annular passage leading thereto and a fuse-carrying member having a tubular center contact which projects beyond an end of said fuse-carrying member and which fits snugly in said passage and engages said contact.

Signed at Fall River, in the county of Bristol, State of Massachusetts, this twentyfourth day of January, 1929.

EDWARD J. BURNS. 

